Railway braking apparatus



June 30,1931. H. L. BONE RAILWAY BRAKING APPARATUS 7 Sheets-Sheet 1 Filed Aug. 21, 1950 Zfourm 0/ ilzzl'dlraisure.

INVENTORZ X 51 r June 30, \1931. H. L. BONE 9 RAILWAY BRAKING APPARATUS v 1 Filed Aug. 21, 1950 v sheets-sneeze To Source 01 Fluid/ n ware.

To SOLZPCQ of Fluid Pressure.

29 I INVENTOR .-....1 #1 78. (am, 6 P a 2153a June 30, 1931. .H. BONE I RAILWAY BRAKING APPARATUS Fild Aug. 21, 1930 7 Sheets-Sheet a To Scurvy of fluid Pressum.

' fluid mssare.

l INVENTOR Z JP-Ax 6w,

June 30, 1931. v|-|. L. BONE 1,812,193

RAILWAY BRAKING APPARATUS Filed Aug. 21, 1950 7 Sheets-Sheet 4 Fluid Pressure.

To LS'oarc-a of Fluid pmssafia INVENTOR I I R0 7 Q June 30,1931. H. L. v130m:

RAILWAY BRAKING APPARATUS Filed Au 21, 1950 7 Sheets-Sheet 5 75 80am of Fluid Pmssare.

Fluid Pressure.

27 INVENTOR my. 9. M W

Emu

June 30, 1931. H. L. BONE 1,812,193

RAILWAY BRAKING APPARATUS Filed Au 21. 19:50 7 Sheets-Sheet e T0 Sow =09 of Fluid I Haid- Pmssam. :6]

. INVENTOR t June so, 1931. H. L. BONE 1,812,193

RAILWAY BRAKING APPARATUS L Filed Aug. 21, 1950 7 Sheets-Sheet .7

To Source of Fluid Xh ssure.

T0 SOUPCQ oi Fluid Pmasar-v.

Patented June 30,1931 1 UNITED "STATES 1,312,153ft I on i HERBERT L; BONE, or swIs'svA n, PENNSYLVANIA, AssIG oR To THE U IO swrron -&sIc+ ALfco1' .Ir AN on swIssvALE, PENNSYLVANIA, .A'CORPORAT'ION or PENN- A SYLVAN IA Application filed August 21,1930. sem 110,476,862.

i My invention relates to railway braking] apparatus, and particularly to brakingappa- 1 pressure motor controlled from a remote ratus of the type comprising a brakingbarjlo cated in the trackway and actuated. by a fluid point.

' I will] describe several forms of 4 railway braking apparatus embodyingmy invention,

"and will then point out the novel features thereof in claims. I 1

In the accompanying drawings,,F1g. 1 1s aview, partly diagrammatic,illustrating one form of railwaybrakingfapparatus operated 7 by a fluid pressure motor controlled from a.

remote point in- ,accordance with my invenw tion. FigsJQ-"lS, inclusive, are slmllar v ews showing modified forms of the apparatus illustrated in Fig. 1,;and also embodyingmy characters 1 and 1* designate the track rails of a stretch of railway ,track. -Located on opposite-sides of mill and extending parallel I therewith are twobraking bars 2 and 3. Two

similar braking bars 2 and 3 extend parallel with rail-1 on op-posite'sides thereof.

The braking bars 2, 3, 2 and 3 are oper ated by a fluid pressure motor M, which in the form here shown, comprises acylinderlcone tainingan auxiliary piston 6 whichisfmow. able between the left hand end of the ,cylin der and an intermediate point in the cylinder,

and a main piston 5 which is movable between the righthand end'jof theacylinder and the auxiliary piston 6. It willbe plain, therefore, that when the auxiliary piston 6 occupies its projected position, in whichit is illustrated in the drawings, the-stroke of the main piston .5 isless than when the auxiliary piston 6 occupies its retracted fposition. The sealing ring of the auxiliary piston 6 is lo; cated" at 6*? in the drawings, and the parts are so proportioned that even when theauXil-Q iary piston occupies its projected position, it v doesnot blank a pipe28 which communicates with the side of the. cylindere. Piston 6-is provided with flutes by means of whichthe pipe 28 may at all times'commu'nicate with 1 RAILWAY BRA ING APBARATUS the region between the pistons 5;and 6. The e [main p-iston'5 ofimotor M isattachedtoia'pis .ton rod 7, which'pist'on rod, in turn, is operatively connected with the braking bars 2,'3,,..-.

2 and 3 by means of suitable operating mechanism, one for'mof which I will now describe.

' pAs-here'shown, thiso-perating mechanism comprlses a link 8'Whichis connected atone end to. the free 'end of the-piston rod 7, and at the other en d'to a lever 9. which is pivotally supported in the trackWa-y at 10.: One end 1 of the lever- 9 connected, through a link 11,-,With a crankflflf'which is pivotally sup ported in. the trackway afi l3i'a-nd the other end of lever 9-is.connected,.through a link 14, with a lever 15 whichis pivotally supported in thetrackway at. 16. It will be seen, therecranks l2 and l5 may. be swung in the same directions when the main piston 5. of motor t M is operated. The free'end of crank'12is operatively connected with the braking'bars 2 and 2 respectively, by means of resilient connections which include springs 17 and-18',

YfOIfG, that the; links 11 and 14 andxthe crank 9 constitute a-toggle by means of; which the v '70 and, similarly,-the free endv-of the crank 15 is operatively connectedwith thelbraking' I bars 3 andu3 by means ofresilient-fconnec tions which include springs 19 and 20. It will I I be seen, thereforefthatwhenfpiston' 5 moves toward theleft, the cranks 12' and 15 are both swung-in a clockwise direction, so that. each i g banis-movedtoward the associated rail into-a braking position in which it en'- gages the side of 'a'wheel of'a railway can traversing the rails landl When the piston 5 moves toward the right, however, the

non-braking positions, in which they'are' out of engagementwith'the wheels of a passlng car. One form of op'eratmg mechan sm of ent of the United States," Serial No. 307,895, filed on September 24, braking apparatus.

1928, s. R i w {cranks 12 and 15 are then swung in a counter clockwise direction, and thebraking bars are moved away from the associated-rails to their i V the-type described is disclosed andclaimed' in'my p e pp a i n forjLetters: Pat-.

each valve V comprises a valve stem 21, biased to an upper position by a spring 22, and pro vided with an armature 23 and a winding 24. hen valve V is energized, valve stem 21 of this valve moves downwardly against tl bias exerted by spr ng 22, and a pipe 26, whic l communicates with the region of cylinder between the auxiliary piston 6 and the ad: jacent end of the cylinder, is then connected with a pipe 25 which is constantly supplied with fluid pressure, usually air, from a suitable source not shown in the drawings. When valve V is deenergized, however, valve stem 21 is moved upwardly by spring 22, and pipe 26 is then disconnected from p; e V hen valve V is energized, valve stem 21 of this valve moves downwardly, thereby connecting pipe 26 with pipe 28, but when valve V is deenergized, pipe 26 is disconnected from pipe 28. VVhe-n valve V is energized, pipe 29 which communicates with the region of cylinder 4 between the main piston 5 and the adjacent end of the cylinder is vented to atmosphere through port 70, but when valve V is deenergized, 25) is disconnected from atmosphere, and pipe which is disconnected from port when this valve is energized, is then connected with port 70. When valve V is energized, valve stem 21 of this valvemoves downwardly and connects pipe 29 with pipe 25, but when valve V is deenergized, pipe 29 is disconnected. from pipe 25. It will be apparent, therefore, that when valve V is energized and valve V is deenergized, the region in cylinder l between the auxiliary piston. 6 and the left-hand end of the cylinder is supplied with fluid pres sure; when valves V V and V are all energized, the regions in cylinder t between the pistons 5 and 6, and between the auxiliary piston 6 and the left-hand end of the cylinder, are both supplied with fluid pressure; and when valve V is deenergized and valve V is energized, the region in cylinder 42 between piston 5 and the right-hand end of the cylinder is supplied with fluid pressure. Furtheu more, when valves V and V are deenergized and valve V is energized, the region between pipe the auxiliary piston 6 and the left-hand end of the cylinder is vented to atmosphere; when valve V is deenergized, the region in ylin der 4,- between the pistons 5 and 6 is vented to atmosphere; and when valve V is energized, the region in cylinder 4 between piston 5 and the right hand end of the cylinder is vented. to atmosphere.

It will be noted that the pipe 26 which communicates with the cylinder 4: between the auxiliary piston 6 and the left hand. en the cylinder is provided with a throt restriction 27. The function of this rest tion will. be explained in detail hereinafter.

The valves V V V and V are controlled in part by a plurality of circuit controllers which are operated in accordance with the position of piston 5. As shown in Fig. 1, there are five of these circuit controllers designated by the reference characters S S S S and S respectively. When the piston 5 occupies its extreme right hand position, in which it is shown in the drawin so that the braking bars are in their open or ineffective positions, contact 3839 of circuit controller S and contact 4L142 of circuit controller 0 are closed. As soon as piston 5 starts to move toward the left, contact 3637 of circuit controller S becomes closed, and upon a little further movement of piston 5 toward the left, contact 3233 of circuit controller S and contact of circuit controller S becomes closed. W hen piston 5 has moved to the left far enough so that the braking bars just the wheels of a car in the braking apparatus, contact 3839 of circuit controller S opens. and upon slight additional movement of piston 5 toward the left contact 411-42 of circuit controller S opens, and con- 38-l0 of circuit controller S becomes closed. Furthermore, just before piston 5 reaches the end of its stroke in this direction, contact 4:1 4:3 of circuit controller S becomes closed.

The valves V are also controlled in part by a plurality of pressure responsive devices, each designated by the reference character P with a distinguishing exponent. Referring to the pressure responsive device 1 for example, this device comprises a Bourdon tube 14 connected, by means of a pipe 81, with pipe 28, and subjected to the pressure in the region between the pistons 5 and 6 in cylinder 4:. The Bourdon tube 44: controls a contact 454l-5 which is closed at all times except when the pressure exceeds a predetermined value, which is just suiiicient to move the braking apparatus to its open position. For example, this pressure might be 30 pounds per square inch. The pressure responsive devices P P and P are similar to the pressure responsive device P except that the Bourdon tubes 4% of these devices are connected, through pipe 30, with pipe 29 which communicates with cylinder 4 between the main piston 5 and the right hand end of the cylinder. The devices P P and P are arranged to operate in succession as the pressure in the right hand end of cylinder 4: increases. For example, for all pressure below 10 pounds per square inch, contact 454L5= of each of these devices is closed. If the pressure exceeds 10 pounds per square inch, however, 'contaot 4545 of device P opens, and if the pressure exceeds 20 pounds per square inch, contact 4-5-l5 of device P close In similar manner, the pressure responsive devices P and P are adjusted to open their contacts 15-45 at 40 and 70 pounds per square inch, respectively, and to close their contacts 45-45 at 50 and 80 pounds per squareinch. Of course these specific pressures are not essential, but" areonly men-5 tioned P P Q of explanatien.

The valves V are further co trolledflby means of a manually operable lever L. which,

as here shown, iscapable of assuming five positions, indicatediby the d'ottedlinesinf the drawings, and designated bythe reference characters p to 29?, inclusive; The lever L operates a contact arm46 which is adapted to engage a selected one or ones of aplurality of fixed contacts designatedby the reference characters 47 to 53, inclusive, The leverL is, also provided witha segment contact 54 so disposed that when the contact arm 46v en-- gages anyone of the fixed contacts 47,48, 49, and 52, the contact. arm also engages the segment contact 54,fbut that the contact arm 46 does not engagethe segment contact 54 when it engages fixed contacts 51 and 53.

The leverL will usually be located at a point remote from'the braking apparatus,

as in the control cabin of a classification yard carretarder system, and will be connected with the. braking apparatus by means of line Wires extending from the control cab-in to the'b raking apparatus.

As shown in the drawings,:levenL'occupies its p or off position, in which" con tacts 46,47,;.46 52 and 46-154 of lever L are all closed, but all ofthe valves V are deenergized. The sup-ply of fluid pressure to all 'regi'ons'of'cylinder: 4 is therefore cut off, and the region between the inainpiston 5 and the auxiliary piston 6 is ventedtoat l 45 of the pres,-v

mosphere. The contacts 45 sure responsive devicesP are all closed'and the contacts 45-45! are all, open. Piston '5 ofmotor lVI occupies its extreme-right hand position in cylinder 4, and the braking bars therefore occupy their retracted or .in'eilecy tive positions. Contact32+33 of circuit con; troller S contact 34-35. of circuit; controller S contact 36- 37:0-'f circuitcontroller-S contact 38f.40 of circuit controller- S and contact 41-43 ofecircuit controller S aretherefore all open, andcontact 38%89- of circuit. controller. 8*,- and' contact 41.',42

of circuit, controllers are closed.- The auice iliarypiston 6 of motor M1 occupies its pro jected position.

- In explaining tus, I will first. assume that the operator wishes to; makea comparatively lightbrake application. To clo-this,-he moves leverL to; its "19 positiomthereby closing contact Hi-48.

tact 38-- 3 9 of circuit contrOller Sffl wire 58,

'winding 24 of valve V andlivewire 59 back to batteryBf VV-alve V therefore-becomes energized and connects pipe 29 with. pipe 25, so that fluid pressure'is now supplied toicylinder 14 between piston 5 and the-right the, Operation of the app ara- A circuitv is then completed; forvalve V and current flows from a suitablesource such as a battery Bnthi'oug h wire55, contact 46,48 of lever 'L, line wire 56","con

an end of the cylinder. This pressure drives piston 5 toward the left, thereby mov ing the braking bars toward theiribraking positions.- It should benotedthat the pressure availableto-commencethe movement of the braking bars maybe built up to full line pressure which may be of the order of pounds per square inch, so. that the. response of the apparatus is very rapid. Shortly after 7 piston 5 starts to move toward the left, contact of circuitcontroller S becomes closed, and a circuit is then completed for,

valve {V -which passes from battery B- j" through wire 55, contact 46 54 of lever, L, llne Wire 60, contact 4545 of pressureresponsive deviceP wire 61, contact-32 33 V of circuit controller S wire 62, winding24.

oivalveV and line wire 59 backfto battery B. -Valve V therefore also becomes ene 'gizedand connects pipe :26 with pipe,25.

When pipe 26 is connected'with pipe 25, full j line pressure is supplied} tocylinder 4 between, the auxiliary piston 6 and the left hand end of the cylinder but, due tothe throttling r'estriction27 in theipipe26, the rate at which thisLp-ressure ca n build up in the cylinder is limitedto a value whichpre 9 cludes any'possibility of shock to the piston,"

6 in case thispiston'does not occupy its full projected position for any reason at the time, valve V becomes energized. 1, When this pressure has once built up, 1t holdsthe-aux- Pismn inits projected positi n, thereby limiting. the stroke of the-main piston.5,

as will be pointed out more fully hereinafter. When the main piston 5 has moved to the left'far enough so that the braking bars are ina positioncorresponding to the working range oftheapparatus, thatis to say, when the braking-bars are in posltion to engage tliewheels of a car in the.bralringapp-aratus,

contact 38 -239 of; circuit controller S opens tinues to move toward the left a sufficient distance to close contact3840 of circuit con-.

troller 8*. When contact 3840 isclosed, if

the pressure in cylinder 4-between piston 5 and the ,riglit hand end ofthe cylinderis .beloWlO pounds per square inch, abranch for the circuit previously traced for valve Y will be completed, which branch may be" traced fromline-wire 5d,,through contact .3840 ofcircuit controller S*,wire 63, con;

tact 45- 45 "of pressure responsive device fro 5 P ,-,and wires 64, 65, '65 and--67 to wire 58.

Underthese 'conditions,.],therefore, valve V will again become energized until thepres-r sure in the right hand endof cylinder 4 ex}v ceeds" pounds .per square, inch, at. which time contact 4545 of pressure responsive device P will open and interrupt this branch, so that valve V will again become deenergized. It usually happens, however, that during the preliminary movement of piston 5, the pressure in the right hand end of cylinder 4 exceeds 20 pounds per square inch so that contact 4545 of pressure responsive device P is closed. Under these conditions, when piston 5 reaches the position at which contact 38-40 of circuit controller S be comes closed, a circuit is completed for valve V which may be traced fron'i battery B, through wire 55, contact 4648 of lever L, line wire 56, contact 3840 of circuit controller 8*, wire 63, contact 4545 of pressure responsive device 1 wires 77, 68, and 69, winding 24 of valve V and line wire 59 back to battery B. Valve V therefore b comes energized and connects pipe 29 with port 70. The right hand end of cylinder 4 is then exhausted to atmosphere until t e i sure in this end of the cylinder has duced below 20 pounds per square inch, whereupon contact 4545" of p essure responsive device P opens and r energizes valve V It will be apparent, therefore, from the foregoing that, when lever L occupies its 19 position, piston 5 is urged toward the left by a pressure of between 10 and 20 pounds per square inch. The movement of piston 5 toward the left under these: conditions is limited by the auxiliary piston 6, which as pointed out hereinbefore, is held in its projected position by fluid pressure which is admitted to the left hand end of cylinder 4 as soon as contact 32-33 of circuit controller S becomes closed, and the parts are so proportioned that the movement of lever 9 caused by this movement of piston 5 does not bring the toggle of which lever 9 forms a part to its dead center posi tion. It follows therefore, that if a car enters the braking apparatus, the braking bars may be forced away from the rails, thereby transmitting the reaction of the wheels, through the operating mechanism, to the piston 5. As a result, the piston 5 may be moved slightly to the left, thereby cushioning the braking action of the apparatus against the volume of air in cylinder 4.

If the operator desires to make a more powerful brake application, he moves lever L to its 72 position, in which contact 4649 is closed. The operation of the apparatus is then similar to that just described with the following exceptions. Valve V is now initially energized, over a circuit which includes contact 4l42 of circuit controller S and which passes from battery B through wire 55, contact 4649 of lever L, line wire 71, contact 4l42 of circuit controller S wires 72, 67 and 58, winding 24 of valve V and line wire 59 back to battery B. lVhen piston 5 has moved to the position where contact 41- 42 of circuit controller S opens, the circuit Just traced for valve V is opened and valve V then becomes deenergized, but

when contact 4143 of circuit controller S subsequently becomes closed, if the pressure in the right hand end of cylinder 4 is then below 40 pounds per square inch, valve V again becomes energized by virtue of a branch for the circuit just traced, which passes from line wire 71, through contact 4143 of circuit controller S wire 73, contact 4545 of pressure responsive device P and wires and 66 to wire 67. If the pressure in the right hand end of cylinder 4 exceeds 50 pounds per square inch when contact 41-43 of circuit controller S becomes closed, so that contact 4545 of pressure responsive device P is closed, valve V then becomes energized, the circuit for this valve passing from battery B through wire 55, contact 46-49 of lever L, line wire 71, con- 4l-43 of circuit controller S wire 7 3, contact 45 of pressure responsive device P wires 74, 68 and 69, winding 24 of valve V and line wire 59 back to battery B. It will be apparent, therefore that when lever L occupies its P position, the piston 5 is forced toward the left hand end of cylinder 4, and is held against auxiliary piston 6, by fluid under a pressure of between 40 and 50 pounds per square inch.

If the operator moves lever L to its 39 position, a circuit is completed for valve V from battery B through wire 55, contact 46-5O of lever L, line wire 76, contact 4545 of pressure responsive device P wires 66, 67 and 58, winding 24 of valve V and line wire 59 back to battery B. Valve V therefore becomes energized and remains energized as long as the pressure in the right hand end of cylinder 4 is below 7 0 pounds per square inch. If the pressure in this end of the cylinder exceeds 7 0 pounds per square inch, contact 45'45 of pressure responsive device P will open and will interrupt the circuit just traced for valve V and valve V will become deenergized. If the pressure in the right hand end of cylinder 4 exceeds 80 pounds per square inch, valve V will become energized and will vent the right hand end of cylinder 4 to atmosphere, the circuit for valve V under these conditions being from battery B through wire 55, contact 4650 of lever L, line wire 76, contact 45-45 of pressure responsive device P, Wires 75, 68 and 69, winding 24 of valve V and line wire 59 back to battery B. Under these conditions, therefore, piston 5 is held against piston 6 by a pressure of between 7 O and 80 pounds per square inch.

If it is desirable to apply still higher braking forces, the operator moves lever L to its 20 position, thereby opening contact 4654 and closing contacts 4651 and 4653. lVhen contact 46-54 is opened, the circuit previously traced for valve V is interrupted,

and valve V becomes deenergized, so'that the supply of fluid'pressure to the left hand controller S ,"wire 7 9, winding 24 of valve V and line wire 59 back to battery '13. Valve V therefore becomes energized, and since all 7 v circuits for valve V are now open so that valve V is deenergized, the left hand end of cylinder 4 is ventedt'o atmosphere contact 46 51 of'lever L becomes closed, a

circuit is completedfor valve V? from battery B through wire 55, contact 46-51 of lever L,

line wire 80, Winding 2450f. valve V and line wire 59 back to'battery YB." Valve V therefore becomes energized sothat' full line pressure is supplied tothe right hand end of cytinder', and since the left hand end of the cylinder is Vented to atmosphere, this pressure moves the pistons 5 and 6 tot-he extreme left 'In'order to restorethe closed-or effectivepos tion to itsopen orin handend ofthe cylinder. 5 It should be noted, however, that due to the throttling restriction 27 in the pipe 26, the rate'at which fluid can escape from the left hand end of cylinder 4 duringthismovement of-piston 6- is limited to a value which causes momentary compression of the fluid which remains in tliecylinder-between the piston and the adjacent end of the cylinder, thereby cushioning the ac-f tion of the entire apparatus." The construction of the parts is such that the additional movementof the piston 5 beyond the point at which it engages piston6 when thispiston occupies its, projected position, brings lever 9 into a position in which the toggle of which itforms'a part is on deadcenter. -When the 7 parts occupy these positions, the reaction of;

the wheels can not betransmitted back to pistoii 5and the; entire forces exerted by the" springs l7, 18,19 and 20 ofjthe resilient con-- king nections are available to hold the bra bars against the wheels of a car. I

It should be observed co'rrespondingto a lower-braking force, the apparatus immediately and automatically reduces the braking pressure to a value correeration in detail. I

effective position, the operator moves lever L to its 7 position -in which itis illustrated in the drawing; The circuit previously traced for valve 7V then becomes closed at contact 4654of lever L, and valve V there- WVhen.

that if the operatormoves the lever L from a position correspo'nde ing to a higherbraking force toa position apparatus from its".

projected position in which it is'illustrated j in the drawings. The closing of contact 46-52 of lever L under these conditions com pletes arcircuit for valve V which is the same as that previouslydescribed for this valve in connection with position 19* of the I lever, except that this circuit now includes contact 4E652 of lever L; instead of} contact 46-53. 'ValV V therefore becomes eenergized, and since valve V is energized, fluid lever L,line wire 81, contact 36 -37 ofcircuit controller S ,"wire 69, Winding 24' of) valve V and line wirer59 back-to battery B.-

Valve 'V fltherefore becomes energized to disconnect pipe 28 from atmosphere andto;

connect a, pipe 29 'with atmosphere When pipe 29 is connectedswith atmosphere;the Q pressure in the right handendof cylinder 4:

is exhaustedfandthe pressure between the pistons 5 and 6 thereforefmoves piston 5 to-- ward the right to restore the braking apparatus't'o itsopen or ineffectiveposition in whichit is illustrated in the drawings, If the pressure in the-region 10f cylinderA-between the piston's5 and 6 eXceedsBOpOunds per square inch during the movementofpis 'ton 5toward the right, contact45-. 45' of preslv I sure responsive device P 'will open and will interrupt the circuitpreviously traced for'k valve 7V Valve V will, therefore, become deenergized and cut'olf the supplyfof fluid] pressure to theregion between the auxiliary piston 6 and'the adj acent end of the cylinder,

and, between the pistons 5 and 6. After the" pressure has again dropped below 30 pounds per square inch, contact45"45' of'pres'sure: responsive device P will again become closed to restore the circuitq for valve V lVhen piston 5 reaches its right hand position, con tact 32-3301? circuit controller S contact 345135 of circuit controller S and contact 7 36%37 of circuit controller Stall open, there-' by opening "the circuits for the valves V V and V respectively. ,1 The valvesV V and V therefore become deenergized and-the partsare then all restored to? their normal 1 conditions "in which they; are illustrated in,

the drawings; When the' valves V f;and V are deenergiz'ed, the pipe 261con'imunicating with'the' left hand end of piston 4Qis blanked,

and the fluid pressure which has already been suppliedto the left hand endof cyl-' 2 indert is now "trapped in the cylinder 4 to holdfthe auxiliary piston 6 in its projected noted thatwhen the-parts are 3 position. V

lt should be in the positions inwhich theyare illustrated in the drawingsyif valveVt' should leak,

pressure might build up on the right hand side of piston 5 tostart the movement of this '8637 of circuit controller S will become closed and will complete the circuit previously traced for valve V so that valve V will become energized, thereby exhausting the right hand end of cylinder 4 to atmosphere. Furthermore, if the leakage past valve V is so great that the piston 5 continues its movement toward the left even after valve V becomes energized, contact 3233 of circuit controller S and contact 34.35 of circuit controller S will become closed. Valves V and V will therefore be come energized and admit fluid pressure to cylinder 4. between pistons 5 and 6, thereby positively restoring the apparatus to its ineffective position. It will be noted that this operation is entirely automatic.

Referring now to Fig. 2, the apparatus here shown is similar to that shown in Fig. 1, except that fixed contact means of line wire 80 as shown in Fig. 1, is connected with line wire 76 by means of wire 82. As a result, when lever L is moved to its 79 position in Fig. 2, valve V instead of becoming energized over the circuit previously described for this valve in connection with Fig. 1, now becomes energized over a circuit which passes from battery B, through wire 55, contact 4651 of lever L, wire 82, line wire 76, contact 454:5 of pressure responsive device P wires 66, 67, and 58, winding 24 of valve V and line wire 59 back to battery B. Fluid is therefore admitted to the right hand end of cylinder 1 until the pressure in this end of the cylinder exceeds 70 pounds per square inch, at which time contact 45-45 of pressure responsive device P opens and interrupts the circuit just traced for valve V, so that this valve becomes de energized. If the pressure in the right hand end of cylinder 4 exceeds pounds per square inch for any reason, contact 45%5 of pressure responsive device P will become closed, thereby completing a circuit for valve V from battery B through wire 55, contact 4651 of lever L, wire 82, line wire 76, contact 45i5 of pressure responsive device P" wires 75, 68 and 69, winding 24 of valve V and line wire 59 back to battery B. Valve V will therefore become energized and will vent the right hand end of cylinder 1- to atmosphere until the pressure again decreases below 80 pounds per square inch, at which time this valve will become deenergized. It will be apparent, therefore, that with the apparatus shown in Fig. 2, when lever L occupies its 19* position, piston 5 is forced toward the left by a pressure of between 7 0 and 80 pounds per square inch in stead of by full line pressure as was the case of lever L, instead of being connected with wire 58 by in Fig. 1. The operation of the apparatus in all other respects is the same as that described in connection with Fig. 1.

One advantage of the apparatus shown in Fig. 2 over that shown in Fig. 1, is that with the apparatus shown in Fig. 2, only seven line wires are required, whereas with the apparatus shown in Fig. 1, eight line wires are necessary, between the car retarder location and the control point at which lever L is situated.

Referring now to Fig. 3, the only difference between the apparatus here shown and that shown in Fig. 1, is that, when lever L is moved to its 29 position in Fig. 3, the circuits which control the valves V and V are controlled by a circuit controller S operated by the motor M, and by the pressure responsive device F instead of by the pressure responsive device P shown in Fig. 1. The circuit controller 8 comprises a contact 8384l which is closed when piston 5 occupies its extreme right hand position, and which remains closed during movement of piston 5 toward the left until shortly after the piston has passed the position in its stroke at which it engages the auxiliary piston 6 when the auxili piston 6 is in its projected position. The circuit controller S also comprises a contact 83-85 which is open when piston 5 occupies its extreme right hand position, but which becomes closed when and only when the piston has moved to its extreme left hand position.

With the apparatus constructed as here shown, when lever L is moved to its 79 position from a position corresponding to a lower braking pressure, valve V becomes energized over a circuit which passes from battery B, through wire 55, contact 4l650 of lever L, line wire 76, contact 838 l of circuit controller S wires 87, 72*, 67 and 58, winding 2% of valve V and line wire 59 back to battery B. Valve V is energized under these conditions by virtue of the circuit previously traced for this valve in connection with Fig. l and, it will be apparent, therefore, that auxiliary piston 6 is held in its projected position, in which it is shown in the drawing, and the main piston 5 is held against piston 6, by fluid at full line pressure.

If lever L is moved to its 79 position from its 20 position, a circuit will be completed for valve V from. battery B through wire 55, contact 4L650 of lever L, line wire 76", contact 8385 of circuit controller S, Wires 86 and 73, contact l5el5 of pressure responsive device P wires 74, 68 and 69, winding 24 of valve V and line wire 59 back to battery B. Valve V will therefore become energized and will exhaust fluid pressure from the right hand end of cylinder 4 until the pressure in this: end of the cylinder drops below 50 pounds per square inch, whereupon contact 4545 of pressure responsive de- 7 vice 1? will openandwill interruptthe cir-r 'cuit Justtraced for valvev so that valve V willbecome. deenergized; At the same time, valve'V will become energized by'vir- .tue of the circuit previouslyztraced for'this valve which is then, closed at contact 46-54" of lever L, and fluid pressure will be-admitted to the left hand end of cylinder 4 so that the'main piston 5 will be forcedtoward the 0 right by the auxiliary piston 6 until the aux iliary piston 6 reaches its-full projected posi-' tion. When the auxiliary piston 6 has reached its full projected position, contact 83-985 of circuit controller's will open and contact 83-84 of circuit. controller S will become ratus for the other positions of the lever is substantially the same as that described in connection with Fig. 1. I f

,Referringnow to Fig; .4, the apparatus here shown is similar to that shown in Fig. 2, except for certain changes in the circuit which is completed for valve V when lever. L is moved to its 37* position, and in thelcir cuits which are completedj'for the valves V and V when lever L is moved to its 39* posi-' t1on. I

As here shown, the circuit which is completed for valve'V when lever L is moved to. its 79* position passes frombattery B throughwire 55, contact 46-58 of leverL, line wire 78*, wire, 93, winding 24 of valve V and line wire 59 back tobattery B, The circuit which is completed for valve V when lever L is moved to its 9 position passes from battery B. through wire 55, contact ,46,47 of lever L, line wire 81, contact 3637 of circuit con-v .1

' der 4 is suppliedwith fluid at full line,pres-' troller S ,-wires 69 and 124, asymmetric unit 90 in its low resistance direction, wire 9.3,, winding 24 of valve V and line wire 59 back tobattery'B. The circuit which is completed.

for valve V3 whenlever L is moved to'its p position passes from battery B through wire 55, contact 46-47 of lever L, line wire 81, contact 36 37 of circuit controllers ;;wire 69, asymmetric unit 91 inits low, re-;

, slstance d1rect1on,.w1re 69 w1nding 24of1 valve V and line wire 59back-to battery B. Thefoper'ation ofthe apparatus here.

shown is substantiallythesame as that press viously described in connection with Figs. land 2, and will be readily understood from an inspection of the drawings. f

It should be pointed out that, with the ap paratus constructed as'here shown,'when any of the circuits previously traced for valve V including the contact 45-45 of the pressure responsive device: P P or P is closed, the asymmetricunit 91 prevents current-from being supplied to valve V and I that' when the circuit' for valve V is closed plied to valve V atcontact 4653 o-f lever L, the asymmetric:

unit 90 prevents current'from being sup- .R'eferrlng now to Fig.5, with the appara tus constructedin the manner here shown, the

control circuits which are completed for the magnet valves when lever L is moved to its 19 or its 39 positions, and the operation of the apparatus under these conditions, are sub-' stantially the same as have been described in detail in connection with Fig. 1. .Thecontrol circuits which are completed ,for the; magnet-valves when lever'L is moved to its 10 position, and the operation of the apparatus under these conditions, are substantially the same as have been described in connection with Fig. 3. i The control circuits which 7 are completed for the magnet valves when lever L s moved to its p p0s1t1on, are the same as those described in COIIHGCtlOIL with current iiows 1 rom battery .13, through wire:

55, contact 464-51 of lever L, line wire 80 asymmetric unlt 92 in lts low res1stance-d1- rectlon, w1re93, winding 24 of valve V and line wire 59 back :to batteryB. A circuit is also completed forj'valve Vat contact 4651 of leverL under these'conditions, and current flows from batteryB through wire 55, conv tact 4651 of lever L, line wire 80*, wire94,

asyinmetric'unit 95in its low resistancedie .rection, winding 24 ofvalve V and line wire;

.59 back to battery B. Valves V? and V" therefore both become energized sothat the left hand endfof cylinder 4 is vented to atmosphere, and thexright hand end of'cylin sure. Piston 5 is therefore moved toitsextreme left hand position in which the toggle" comprisim gqthe lever 9 and links 11" and 14 (Fig. l) is on'dead-center, so that if a car then. occupies the braking apparatus," the ert their maximum braklngforce. I

= It shouldbe noted that with the apparatus brakin "bars will. engage the wheels; and exconstructed in the 'manner as shown, the I current when valve V is energized over any of thecircuits for valve V except the circuit including the asymmetric unit 95. 5

. Referring now to Fig. 6, the only 'difie rs ence between the apparatus here shown and; that shown in is that when lever L is moved to its 39? position in Fig. 6 ,IvalveswV and Vflin'stead of being controlledby circuit asymmetric unit 92' prevents current from energizedoverxthe circuit including contact. t I no unlt 90, and that the, asymmetric unit 95 85 Fig.4, and theoperation of the apparatus 1 are in F The operation of the ap (l w i be readily nndeis pcction or the drawings in connection with the (cscription oi the preceding fi ures.

Re "cg next to 7, here shown lover .s provided with second c 4L6 adapted to engage a selected one or ones of a plurality of tired (ou t: nor that when contact arm to engages a given fir l contact, the contact arm &6 will e a i .iilar fixed contact designated by a. snni lar reference character withthe distinguish ing exponent a. For c1: "lllplt, wlr' ever L occupies its 7) position, in which 1., s illustrated in the drawing, so that the contact arm 46 engages fixed contact 47, contact arm 4 .6 lined contact 17; l lcva occupies its Q31 position, so t 46 engages fixed contact 48, contact 4 ga s fixed contact 1-8, etc. The cont c l6 arranged to contr the supply or rent to certain of the va s V from a SOL of electromotive force here shown as a battery C.

The operation of the apparatus here shown is as follows: WVhen the parts are in the positions in which they are illustrated in the drawing, if the operator Wish-es to make a comparatively light brake application, he moves lever L to its 29 position. A circuit is then completed for valve V at contact a6 -4t8 of lever L, and current flows from battery C through line wire 59, winding 24. of valve V wire 58, contact 3839 of circuit controller S, asymmetric unit 98 in its low resistance direction, line wire 78", wire:

100, contact 4CG4S of lever L, and wire 101 back to battery 0. Valve V therefore becomes energized and admits fluid to the right hand end of cylinder f at full line pressure so that piston 5 moves towards the left, thereby moving the braking apparatus towards its effective position. Soon after piston 5 starts to move towards the left, contact 32-33 of circuit controller S closes and completes the circuit previously traced for valve V in con nection with Fig. 1. Valve V therefore also becomes energized and admits fluid pressure to the left hand end of cylinder 4 to hold auxiliary piston 6 in its projected position. When the piston 5 has moved to the position Where the braking apparatus is in its effective position, contact 38-39 of circuit controller S opens, and upon slight additional movement of piston 5 towards the left, contact 384EO of circuit controller 5* becomes closed. When contact 3839 opens, the circuit for valve V which was previously closed at this contact is opened, so that valve V becomes deenergized, and when contact 3S l0 becomes closed, if the pressure in the right hand end of cylinder l is then below 10 pounds per square inch so that contact 4:5 4c5 of pressure responsive device P is closed, a branch for the circuit just traced for valve V is closed. l his branch passes from w' re 58, through wires 6?, (S6, and 6st, contact as-as of pressure responsive device P wire {53, contact 38-4l0 of circuit controller S, and asymmetric unit 98 to line wire 78 Valve V therefore again becomes energized, and admits fluid to the right hand end of cylinder 4; until the pressure in the right hand end of the cylinder exceeds 10 pounds per square inch at which time this valve again becomes deenergized. If the pressure in the right hand end of cylinder 4 exceeds 20 pounds per square inch when contact 38* l0 of circuit controller 8* becomes closed, so that contact 454:5 of pressure reauponsive 5 ice P is closed, as is usually t e case, a circuit is then completed for valve V which passes from battery G through line wire 59, winding 24 of valve V Wires 69, 68 and 77, contact 45-5 of pressure responsive device P wire 63, contact 3840 of circuit controller 8*, asymmetric unit 98 in its lower resistance direction, line wire 78 wire 100, contact 46- l8 of lever L, and wire 101 back to battery C. Valve V therefore becomes energized and exhausts fluid from the right hand end of cylinder t until the pressure is below 20 pounds per square inch.

if the operator wishes to cause a more powerful brake application, he moves lever L to its 72 or p position instead of its 39 position. Under these conditions, the control circuits which are completed for the valves, and operation of the apparatus are the same as were previously described in connection with Fig. 1 for similar conditions.

If the operator moves lever L to its 79* position, the circuit previously described for valve V in connection with Fig. 2 is closed at contact 46-51 of lever L, so that valve V then becomes energized and admits fluid pressure to the right hand end of cylinder 4 until the pressure in this end of the cylinder Xceeds pounds per square inch, at which time contact 45e5 of pressure responsive device P opens and deenergizes valve V A circuit is also completed under these conditions for valve V over which current flows from battery B through wire 55, contact l653 of lever L, line wire 78, wire 102, asymmetric unit 103 in the low resistance direction, Wire 104, contact 3435 of circuit controller S wire 7 9, winding 24: of valve V and line wire 59 back to battery B. Valve V therefore becomes energized and vents the maximum-braking forceupon the wheels of left hand'end of cylinder 4:;to atmosphere thereby permitting piston 5 "to move "to its extreme left hand position. It will be apparent, therefore, that when lever-L occupies its p p'osition, the braking bars exert their a car occupying the braking apparatus.

If, when the braking apparatus is in its effective position, the operator' wishes to restore 1t to its ineffective position, he moves lever L to its 11 or off position. Under these conditions, the circuit fori ralve'ejv pre viously' described in connection with Fig. '1

' end of the cylinder is vented to atmosphere. The auxiliary piston 6 "isitherefore moved w to its projected position, and the main piston -5 is 'moved toits extreme righthand position,

is closed at contact 4647 of lever L, and the circuit previously described for valve V is 7 also closed at contactl'6'54oflever L. -Fur- 'thermore, a circuitis now completed for valve 7 j V 2 at contact 46.- 52 of'lever L, and current 'flows from batteryB, through wire 55, contact 46-52 of lever'L,-flin'e wire 78', wire a result, the valves V, V and V all become energized so 'tha t fluid ata' pressure of 30 pounds {per square inch-is adi'nittedjto the region of cylinder' l between the auxiliary piston 6 and the adjacent end of the c'ylin-' der, and to'thef region of the cylinder be tween the auxiliary piston ti and the main piston 5, while. the region of cylinder 4 be tween the main piston 5 andthe right hand in which it is illustrated in the"drawings.

hen the piston 5 reachesits extreme right hand position, contact32- 33of circuit'con- Stroller S contact 34%3501 circuit controller S and contact 86%37 of circuit controller S all become opened, so that the valves V V and V thenbecome -deenergi zed.,;The

apparatus is then restored to the "condition in which it is illustratedin the draw ngs.

' It should be pointed out that with the ap- V paratus constructedin'the manner just described, the asymmetric unit 103' prevents current from being supplied'from battery C to the winding 24-of valve V over line wlres 59 and 78? whenlever L occupiesits p posi- 'tion, and thatthe asymmetric unit'98 pr'e vents current from beingsupplied to the valve V over line wire 7 8 when the lever L occupies its or p positions One advantage of theappara'tus shown in 7 over that shown in any of thGIDIG.

F1 v ceding views is that, with the apparatus shown in Fig. 7 only six line wires are "required, whereas with the "apparatus shown in any of the preceding views, at least seven,

line wires are necessary.

Referring now to Fig. 8, the apparatus here shown is similar to the apparatus shown in Fig. 7, with the following exceptions. here shown, when leverL is moved toits p position, valve V insteadof becoming energized over the circuit described in 'connection with Fig. 7, now becomes energized by virtue of EL ClT CllltfWlllCh is controlled; by

contact 46F '51 of lever L, and overwhich current flows from battery C-through line wire 59, winding 24 of valve Vflwire 106, asymmetric unit 107 initslowresistance direction, line wire 60, wire 108, contact 4l6 .51 of lever L, and wirelOl back to battery G. -Under' thesefconditions, there'- fore, valve V 1 admits fluid at full line pressure to the right hand end of cylinder 1in stead of fluid at a -pressure'between70 and pounds per square ,inch as is the casein current when contact 46 ,54 of lever Lis closed, an asymmetric unit 105 is included Fig. 7.; Furthermore, since a part of the 1: circu t ]L1St described is'common to the circuit overwhich valve V is supplied with in the circuit-forvalve V in such manner that valve V is prevented from being sup plied withcurrent whe nthe circuit for valve V is closed. The operation of the apparatus w i in all other respects is the same as that describedinconnection with Fig. 7.

hereshown is similar tothelapparatus shown L is moved to its p position, the valvesV and V are controlled by the circuit controller S and by pressure responsive device P in the manner previously described in connection with Fig.8 instead of byfthe pressure I responsivedevice" 'P 1shown ;in Fig. 8, so

that, under these conditions, piston'5 is held against piston 6 by full line pressure instead of by a'pressiire o'f'between 7 0 and 80 pounds per square inch, *as' isthe case when these valves are controlled'by'the pressure responsive device'P Theoperation of the apparatus will be readily understood from an inspection ofthe drawings in connection with the description of the preceding views.

" -Referring now to Fig. 9,' the apparatus in Fig. 8 with the exception that when lever Referring now to Fig. 10-, with the; as '1 when the braking" apparatus is in its non-cf paratus constructed in 4 the. manner here' shown, fleverL s moved to 1ts 79 position fectiveposition, a circuit for valve V is com- 7 pleted at conta'cti4648 of lever L, and. current flows from battery B through wire 55,

contact 46%8 of lever'L, line wire 56F,'wire 109, asymmetric unit llO'in its low resistance direction, wire 111, contact 38- 3910f: cir- 'cuitcontroller-S ,*wire 58,- winding 24*of valve V and line wire59 back to battery B; Valve V therefore becomes energizedand ad v mits' fluid at full line pressure tothe right hand end of cylinder 4'to move piston '5 to;-

wards the left, and" the braking bars towards i .their,brakingpositions. --Shortly after piston 5 starts to move towards the left, a circuit for valve V is completed at contact 32*33 of cir- I i v of valve V wire 62, contact o2-33 of circuit controller S wire 61, contact 4545" of ressure res )onsive device P which contact remains closed since the pressure responsive device is not connected to that part of the cylinder between piston 6 and the extreme left end of the cylinder, line wire contact 46 54 of lever L, and wire 101 back to battery C. Valve V therefore also becomes energized, and admits fluid at full line pressure to the left hand end of cylinder 4 to hold auxiliary piston 6 in its projected position. V hen the braking apparatus reaches its effective position, contact 3839 of circuit controller S opens and contact 3840 becomes closed. lVhen contact 3839 opens, the circuit for valve V which was previously closed at this contact is interrupted, and when contact 38-40 becomes closed, if the pressure in the right hand end of cylinder 4 is then below 10 pounds per square inch, a branch for the circuit just traced for valve V is closed. This branch passes from wire 111 through contact 3840 of circuit controller S wire 63, contact 454c of pressure responsive device P and wires 64, 65, 66 and 67 to wire 58. Valve V therefore again becomes energized, and admits fluid to the right hand end of cylinder 4 until the pressure in this end of cylinder 4 exceeds 10 pounds per square inch, at which time contact 4545 of pressure responsive device P opens and deenergizes valve V If the pressure in the right hand end of cylinder 4 e2;- ceeds 20 pounds per square inch when contact 3840 of circuit controller S is closed so that contact 45 45 of pressure responsive device P is closed, a circuit is then completed for valve V over which current flows from battery B through wire 55, contact 46-48 of lever L, line wire 56, wire 109, asymmetric unit 110 in its low resistance direction, wire 111, contact 38-40 of circuit controller S", wire 63, contact 4545 of pressure responsive device P wires 77, 68 and 69, winding 24 of valve V and line wire 59 back to battery B. Under these conditions, valve V becomes energized and vents the fluid pressure in the right hand end of cylinder 4 to atmosphere until the pressure decreases below 20 pounds per square inch, whereupon contact 45-45" of pressure responsive device P opens and deenergizes valve V It will be apparent, therefore, that when lever L occupies its 22 position, piston 5 is held against piston 6 by a pressure of between 10 and 20 pounds per. square inch.

If, now, lever L is moved to its 79 position when the braking apparatus is in its ineffective position in which it is illustrated in the drawings, another circuit for valve V is then closed at contact 4649 of lever L, and cur rent flows from battery B through wire 55,

contact 4649 of lever L, line wire 71, Wire 112, asymmetric unit 113 in its low resistance direction, wire 114, contact 4142 of circuit controller S wires 72, 72 67 and 58, winding 24 of valve V and line wire 59 back to battery B. Valve V therefore becomes ener gized and admits fluid at full line pressure to the right hand end of cylinder 4 to move piston 5 toward the left and the braking apparatus to its eifective position. Shortly after piston 5 starts to move, the circuit previously traced for valve V including contact 46-54 of lever L becomes closed at contact of circuit controller 8*, so that valve V becomes energized and admits fluid at full line pressure to the left hand end of cylinder 4 to hold the auxiliary piston 6 in its projected position. When the braking apparatus reaches its effective position, contact 4142 of circuit controller S opens, and contact 4143 becomes closed. When contact 41-42 opens the circuit for valve V which was previously closed at this contact is opened, and when contact 4143 becomes closed, a

branch for the circuit just traced for valve V becomes closed 1f the pressure in the right hand end of cylinder 4 is below 40 pounds per squa re inch. This branch may be traced from wire 114 through contact 41-43 of circuit controller S wire 73, contact 4545 of pressure responsive device P and wires 65, 66 and 6? to wire 58. Under these conditions, valve V again becomes energized and admits fluid to the left hand end of cylinder 4 until the pressure in this end of the cylinder exceeds 40 pounds per square inch, whereupon contact 4545 of pressure responsive device P opens and deenergizes valve V If the pressure in the right hand end of cylinder 4 increases beyond 50 pounds per square 1 inch, contact 45-45 of pressure responsive device P closes, and completes a circuit for valve V over which current flows from battery B, through wire 55, contact 46-49 of lever L, line wire 71 wire 112, asymmetric unit 113, wire 114, contact 41-43 of circuit controller S wire 73, contact 4545 of pressure responsive device P wires 74, 68 and 69, winding 24 of valve V and line wire 59 back to battery B. Valve V therefore becomes energized and vents the right hand end of cylinder 4 to atmosphere until the pressure has decreased below 50 pounds per square inch. It will be apparent, therefore, that when lever L occupies its 27 position, the piston 5 is held against the auxiliary piston 6 by a pressure of between 40 and 50 pounds per square inch.

If lever L is moved to its 39 position when the braking apparatus is in its ineffective position, a circuit is completed for valve V at contact 4650 of lever L, and current flows from battery B through wire 55, contact 4650 of lever L, line wire 76, contact 8384 of circuit controller S wires 82, 72 67 and .58, winding .24 of 'valve V, and line wire 59 back to battery. B." .Fluid at full line pressure is therefore admitted to the right hand 1 end of cylinder'4 to drivepiston5 towards the left and the braking "apparatus towards its effective positionif Shortly after piston 5 starts to move, the circuit previously traced for valveiV becomes closed atcontact 32 -33 of circuit controller S and valve? therefore becomes energized and admits fluid pres- I sure to the left handend of .cylinder4' to hold piston 6 in its projected position. As pointed 4 out hereinbe'fore, contact: :8 3 84 of circuit controller S jremains closed until piston 5 the auxiliary piston 6 when this pistonjoc-v moves past the position at which it engages cupies itsprojectedposition, and it will heapparent, therefore, that, under these Icondi:

tions, valve V remains energized sothat piston i 5 is held against piston 6 by full line pressure. .1 1,

1 Iflever L is movedto 1ts p .posiitionwhen the braking apparatus is in its ineffective po- -sition,,a' circuit is-complet'ed for valve V whichis similartothe circuit which becomes closed. forvalveV. when lever L is moved to its p position exceptthat this latter circuit includes contact 46%:51 of'lever L and wire 82iinstead of contact 46.50-of lever Lr .Pis-

ton 5,, is thereforemov'ed to the left by fluid at full line pressure. Furthermore, as soon as contact 3435 of:circuit controller S becomes closed a circuit is also completed for valve v gand current flows-from battery C through line .-wire "59, windi'ng24 of-valve V wire .79, contact. 34-.. 35'. of circuit controller S wire 116, asymmetric unitll'kinitslow resistance direction, WiI'61118, line wire-71, v

wire 115, contact46 53 of 1ever-L,and wire 101 back'tobattery C. Valve V atherefore .becomesienergized and connects the left hand end of cylinder 4 to atmosphere, so that the pistons 5 andfi now move to their extremeleft hand positions When piston 5reaches its extreme .left'hand position, contactf83+84 of circuitcontrollerS" opens and contact 83%85 becomes closed. When contact 8384 opens, the circuit forjvalve V isinterrupted and. valve V be'comesideenergized When contact -83--85 becomes closed, if the p'ressure' ingthe right hand endo-fcylinder 4 is then fb'elow' 70 pounds per squa'reinch, a ibranch is completed for'the'circuit for valve Vt: This branch .passes'fromline wire 76 through contact 83-85 of circuitcont'roller S,' 'wir e 119, contact -45 I.Iof pressure resp'onsive device P and wires 66 and 67 to wire 58;

Valve Vii then again"becomes*energized and admits fluid'p ressure" to the! right hand-end of cylinder 4 until'stherpressure in this end ofthe cylinder exceeds 70 pounds'persquare inch; If the pressure in the right hand end of: cylinder 4.:exceeds pounds per square inch when contact 83- 85 of: circuit control: lerTS is closed, a circuit is then completed for valve V over current flows from bat te'ry B throughwire 55, contact '46 5l off lever L,'wire 82,1ine wire'76, contact 83185,

i of circuitcontroller S", wire 119, contact 45- 45". of pressure responsive. device B",

wires. 75, 68 and 69, winding 24 of valve V square inch.

If, when the brakingapparatus in its effective. position, the operator moves lever- L to its p orofi pos1t1on,thefc1rcu1t prevrously traced for valve V? becomes closed at becomes energized andadmits fluid' pressure tothe left handjend of cylinder4'," so'th'a't piston "6 ismoved towards its projected position. 'A circuit is alsocompletedfor valve flows from battery C through line' wire 59,

winding '24 of valve V Wire 69,. contact '86-37of circuit controller S wire 120, asym-' metric unit 121' in its low resistancedi-recitio'n, Wire 122,1ine wire 56, wire-123, contact battery C. Valve V therefore becomes'ener'gizjedto connect pipe 29 with atmosphere and to 'dlsconnect pipe 28 from atmosphere,

thereby]exhaustingthe right hand-endof cylinder 4 and preventing the escapeo ffluid v p from cylinder-4 between the pistons '5 and v 6.; Furthermore, a circuit'is completed for valve V which is similar to the circuitwhich was previously closed for this'valveatcon} j tact '46 53 of, lever L when lever L occupied its pposition, except 'that this circuit now J includes contact 4b ""52 "of lever L instead 4 ofcontact-46 53 [Valve/V therefore also becomes energized, so that fluid. pressure is I admittedto the; region of-cylinder 4 between the pistons 5 and-6; This 'pressur'ezmoves piston 5 to i tsfextreme right hand position,

therebymovingthe braking apparatus-to its ineffective position. When the piston reaches its extreme right 5 hand position, 1 contact 32-33 of circuit controller S ,co1'1tact l of circuit controller S and contact- 36 37 of circuit controller S open,thereby deen'ergizing' the valves V ,V and V respectively; The apparatus is then restored to the condi 'tiori which it is-illu-stratedin 'the draw: i v v i l d v y moved to its p position in'Fig. 11, the "valves V andV- are 'controlled by the circuit 0011- v I I Referringnow;toFigQll, thebnlydifi'er encebetween the apparatus here shown and thatsho-wn in-Fig. 10 is that when lever Ljis. n

trollerS and the pressure responsive device P ",.in a manner which will be apparent from an inspection of the drawings and the description of the preceding views, insteadof by the circuit controller S and pressure responsive device P with the result that when the piston has moved to its extreme left hand position under these conditions, the

nection with Fig. 10.

Referring now to Fig. 12 the apparatus here shown is similar to that shown in Fig. With the following exceptions. When lever L is moved to its 79 position in Fig. 12, valve V instead of becoming energized over the circuit shown in Fig. 10, now becomes energized by virtue of a circuit passing from battery B through wire 55, contact 4651 of lever L, line wire 60*, asymmetric unit 107 in the low resistance direction, winding 24 of va1veV and wire 59 back to battery B. As

result under these conditions valve V remains energized as long as lever L occupies its position. Furthermore, since part of the circuit just tracedfor valve V is common .to the circuit which is completed for valve V when contact 4654 of lever L is closed, an asymmetric unit 105 is inserted in the circuit for valve V in a manner .to prevent improper energization of valve V The operation of the apparatus here shown will be readily understood from an inspection of the drawings in connection with the foregoing description of Fig. 10.

Referring now to Fig. 13, as here shown circuit controller S is so designed, that its contact 3435 will not become closed until after piston 5 has moved to the left far enough so that the braking bars engage the wheels of a car in thebraking apparatus. Furthermore, the circuits for the magnet valves have been rearranged in a manner which makes the use of contact 4143 of circuit controller 8, and contact 3940 of circuit controller S shown in the preceding views, unnecessary.

With the apparatus constructed as here shown, if lever L is movedto its p position, a circuit is completed for valve V at contact 4648 of lever L, and current-flows from battery B through wire 55, contact -4648 of lever L, line wire 56, asymmetric unit 110 in its low resistance direction, contact 3839 of circuit controller S wire 58, winding 24 of valve V and line'wire 59 back tobattery-B. Valve V therefore becomes energized and admits fluid pressure to the right hand end of left.

cylinder 4, so that piston 5 moves toward the Shortly after piston 5 starts to move toward the left, a circuit for valve V is completed at contact 3233 of circuit controller S and current flows from battery C through line wire 59, wire 133, contact 3%33 of circuit controller S wire 132, winding 24 of valve V wire 130, contact 45 of pressure responsive device P line wire contact 46 54*"- of lever L, and wire 101 back to battery C. Valve V then also becomes energized, and admits fluid at full line pressure to the left hand end of cylinder 4, thereby holding auxiliary piston 6 in its projected position. left far enough so that contact 38-39 of cir- Nhen piston 5 has moved to the cuit controller 5* becomes opened, the circuit ust traced for valve V is opened, but, if

the pressure in the right hand end of cylinder 4 is then below 10 pounds per square inch, so that contact 4545 of pressure responsive device P is closed, valve V will remain-energized by virtue of a branch for the circuit just traced, which branch passes from line wire 56 through asymmetric unit 110 in its low resistance direction, wire 147, contact 4545 of pressure responsive device 1 and wires 64, 65, 66 and'67 to wire 58. It'usually happens, however,- that during the prelimi nary movement of piston 5, thepressure in the right hand end of cylinder 4 builds up to a value in excessof 20 pounds per square inch, so that contact 4545 of pressure responsive device 1 is open, and contact 4545 is closed. Under these conditions,

when contact 3839 of circuit controller's becomes opened, valve V will become deenergized. Ifthe pressure in'the right hand end of cylinder 4' stilleX-ceeds 20= pounds per square inch when contact '8435 of circuit controller S becomes closed, a circuit is then completed for valve "V and current flows from battery 13 through wire 55, contact 4648 of lever L, line wire 56", asymmetric unit llOinits low resistance direction, wire 147, contact 4545 of pressure responsive device P wire 135, contact 3435 of circuit controller S wires 145 and 69, winding 24-of valve V and line wire 59'back tobattery B. Under these conditions, valve V becomes energized, and vents the right hand end of cylinder 4 to atmosphere until the pressure in this end of the cylinder decreases below .20 pounds per. square inch, whereupon contact 4545 of pressureresponsive device P opens and-deenergizes valve V It will be apparent, therefore, that with the apparatus constructed as here shown, when lever L occupies its 79 position, piston -5 is held against piston 6 by a pressure of'between 10 and 20 pounds per square inch.

I will now assume that with the apparatus constructed in the manner here shown, lever L is moved ilO'iiJSj92POSl13l OIl when'the braking apparatus is in its ineffective position.

- 'ergized Under these conditions, a circuit is completed for valve V at "contact 46 -49 of lever -L, and current flows. from battery B through Wire 55, contact 461-49 of lever L, linewire 71 asymmetric unit 139 in its low resistance direction; wire 140, Contact 414-42 of circuit battery B; Valve to move, the

circuit controller S so that valve V 1 becomes energized and admltsvfluid at full line pressure to the left-hand end of cylinder-'4to hold t I I V If lever 'Lc's moved toitsqu position when.

the auxiliary piston 6 in'its projectedposi-v 2 mm. *When the piston 5 position :at which circuit just traced for valve V is opened, but ifthe' pressure in the right hand'end oficyle inder 4; is thenjbelow 40 pounds per square 7 inch, valveV remains energizedby virtue of a branch forlthe circuit just traced for'valve i V*, which branch-maybe traced from wire 140 through wire 146, co-ntact 45-45 iOf' pres-.'

sure responsive device P, and Wires'65 and 66 to' Wire 67 If, however,the pressure in the I righthand endc of-cylinder 4exceeds 40 pounds per square'inch when contact 41-42 opens, contact -45 ofpressure responsive device 1? will be opened, so that this branch 35 will be open, and valve V will then become deenergized. If, when contact 34 35 of circuit controllerS becomes closed, the pressure in-"th e right hand end, of cylinder '4 exceeds pounds per square inch, so thatcontact 45-"45 'o pressure responsive device 1 is closed, a'circuit is'then'completedfor valve: andcurrent flows from battery B through" contact 46 -49 oflever L,=line wire 71", asymmetric unit 139 in its low resistance direction,

it -wires 140'and 146,4?011ba6tj45I-7-45 of pres-v sure responsive device' P 9,wires 134 and 435, contact 34- 35 of circuit controller S wires 145 and B9, winding'24 hand end of cylinder 4to atmosphere until the-pressure has decreased lbelovv 50"p ounds 5 per square inch." Under these COIldlC-iOIiSf I I I I I I tact 45''45 of pressure responsive dev ce P? I therefore,=piston 5 is urged toward the left by a pressure of er square inch..; I

If lever L is moved to 5 is; pain when the braking apparatus is 1n 1tsi'nefiecti-ve p0 i sition, a" circuit iscompleted for valve V at -contact 46 5Q of lever L, and c urrent flows y from battery B through wireiss, contact; 46-+50 of lever L, line wire 76*;contact 83-84 67 and Y 58, winding'24 of valve V, and line wire 59 therefore be of circuit controller S wires] 87,72,

5 back to battery B; {Valve projected position, and 'it I has moved to "the contact'41 42 opens, the

"vents th e'left hand end ofcylinder 4-to at-,

I I of {valve V? and line} wire 59 back to battery-"B. ValveV there *iore becomes energized and vents the right bet Weem4O' and5O pounds II I I c becomes energized an'dadmitsifiuldpressure towardthe left. 1 When contact 32-33 of c ircuit' controller S fbecomes closed,the' circuit closed, and valve T -becomes energized, so

. that'pistonfifis held in, its projectedposition.

byfiuid atfull line pressure. A s pointed out hereinbefore', zc'ontact 833 84 of circuit con-i.

troller S remains'closeduntil piston 5moves' ,5 1 I past the position at which it engages the aux-n iliary piston 6 when this piston occupies will-be. apparent, therefore, that under theconditions now: be-" ing described, valve V remains energized so i andpi'ston 5 i's.:held againstzpiston 6,.by 1111 line pressure.-* 1;

position, a, circuit: is completed for valve:

V whichis {similar to the; circuit, which V is;

completed for valve V when lever L lS'IilOVed" to its 37 position,except that the circuit now.

includes contact 46751 'oflever Land wire I 82, instead of contact 46-5.0 ofllever L; -Pi's-f I I ton 5 is thereforemoved toward the left by.

fluid at 'fullwline pressure. urthermore,';as I

soon as contact 3283 0f circuit controller 7 S becomes closed, a circuit is also completed" for valveiv and current flows frombattery 'G through line Wire'59, wire i 138, contacts 32%33 ofcircuit'contrfoller S ,,wire 132,,Windk I I I ing 24 of valve V wire144, asymmetric unit T 143' in its low resistance direction, wiref 142,

line wire 71*, wire- 115, contact 46 v53".of lever L, andwirelO-l backto battery G. Valve V? therefore becomes energized and mo'sphere, so that the pistons 5 and 6 move to I their extreme left hand positions. When piston 5 reaches its extreme le ftfhand position, contact 83- 184 of circuit controller S 'opens, and contact 83- 85 becomes closed; Whenf v interrupted, and 'valv eVt' becomes deenj i contact 83 -84 opens, the circuit for valve V ergized. When cOnta ctL 8?85 "becomes closedjif the pressure in the. right hand end of cylinder 4'is" then below 70 p0undstper squarejinch, a branch is "completed for, the circuit-just traced for valve vftwhichIbranch' throughcontact; I

passes from line wire '76? 83 85 of circuit controller S?,-wi re.1 19, con-- and Wire 66 to Wire 67. Valve V thenagain of circuit controllerlS?'isclosed, a circuit is; I II completed for valve 'V ,land' current flows? from battery- B through Wire 55, ,conta ct gprevrously "described for valve "V b comes i 0, A that piston 6 is held inlitsprojectedposition, 

